When a bundle of relatively slender cables or a relatively small-sized FPC is electrically connected with a main circuit board, such as a solid printed circuit board, on which various electrical parts are directly mounted, there has been often proposed to use a first electrical connector on the side of cables or FPC, with which the bundle of cables or the FPC is connected, and a second electrical connector on the side of circuit board, which is fixed to a main circuit board to be electrically connected with the same and with which the first electrical connector is engaged. The first electrical connector is operative to function as a mating electrical connector to the second electrical connector and the second electrical connector is operative to function as a mating electrical connector to the first electrical connector.
In such a case, the first electrical connector constitutes a plug type electrical connector which comprises, for example, an insulated housing which is provided thereon with an engaging portion forming a connectively engaging protrusion on which a plurality of conductive contacts are arranged to be electrically connected with the cables or the FPC. Usually, the first electrical connector constituting the plug type electrical connector comprises also a conductive shell or cover formed by means of processing a metal thin plate and mounted on the insulated housing for covering partially the same to be grounded for shielding the conductive contacts arranged on the connectively engaging protrusion provided on the insulated housing from electromagnetic wave noise coming from the outside. The second electrical connector operative to function as the mating electrical connector to the first electrical connector constitutes a receptacle type electrical connector which comprises, for example, an insulated housing on which an engaging portion forming a connectively engaging opening into which the connectively engaging protrusion provided on the insulated housing of the first electrical connector is inserted is provided. In the connectively engaging opening provided on the insulated housing of the second electrical connector, portions of a plurality of conductive contacts, an end of each of which constitutes a terminal connected electrically with the main circuit board, are arranged. Usually, the second electrical connector constituting the receptacle type electrical connector comprises also a conductive shell or cover formed by means of processing a metal thin plate and mounted on the insulated housing for covering partially the same to be grounded for shielding the conductive contacts arranged in the insulated housing from electromagnetic wave noise coming from the outside. Under such a situation, when the connectively engaging protrusion provided on the insulating housing of the first electrical connector is inserted into the connectively engaging opening provided on the insulated housing of the second electrical connector to engage with the same, the conductive contacts of the first electrical connector come into contact respectively with the conductive contacts of the second electrical connector to be connected electrically with the same.
With the above-described first electrical connector constituting the plug type electrical connector with which the bundle of cables or the FPC is connected and the second electrical connector constituting the receptacle type electrical connector fixed to the main circuit board, when the connectively engaging protrusion provided on the insulated housing of the first electrical connector with which the bundle of cables or the FPC is connected is engaged with the connectively engaging opening provided on the insulating housing of the second electrical connector which is fixed to the main circuit board, it is required for a set of the first and second electrical connectors put in engagement with each other to have a size reduced to be as small as possible in an altitudinal direction on the main circuit board so as to reduce an open space surrounding the main circuit board. For meeting such a requirement, the second electrical connector constituting the receptacle type electrical connector is fixed to the main circuit board in such a manner that the connectively engaging opening is made open in a direction in parallel with an outer surface of the main circuit board and the first electrical connector constituting the plug type electrical connector is moved along the direction in parallel with the outer surface of the main circuit board for causing the connectively engaging protrusion to engage with the connectively engaging opening in the second electrical connector.
When the connectively engaging protrusion provided on the insulated housing of the first electrical connector constituting the plug type electrical connector is engaged with the connectively engaging opening provided on the insulated housing of the second electrical connector constituting the receptacle type electrical connector in such a manner as mentioned above, it is required that first the connectively engaging protrusion is set to face the connectively engaging opening at an appropriate position in an appropriate direction and then the connectively engaging protrusion thus set is moved appropriately to the connectively engaging opening so as to engage with the same. Accordingly, there have been previously proposed some measures or means for meeting the requirements for the connectively engaging protrusion provided on the insulated housing of the first electrical connector constituting the plug type electrical connector. In one of such measures or means proposed previously, the first electrical connector constituting the plug type electrical connector is provided with an engaging guide member for projecting to the outside of the connectively engaging protrusion and the second electrical connector constituting the receptacle type electrical connector is provided with an engaging receptacle opening for engaging with the engaging guide member to receive the same. When the connectively engaging protrusion provided on the first electrical connector is put in engagement with the connectively engaging opening provided on the second electrical connector, prior to the engagement of the connectively engaging protrusion with the connectively engaging opening, the engaging guide member provided on the first electrical connector is engaged with the engaging receptacle opening provided on the second electrical connector to be received by the same so that a position at which the connectively engaging protrusion faces the connectively engaging opening and a direction along which the connectively engaging protrusion is moved to the connectively engaging opening are predetermined and thereby the connectively engaging protrusion is set to face the connectively engaging opening at the appropriate position in the appropriate direction and then the connectively engaging protrusion thus set is moved appropriately to the connectively engaging opening so as to engage with the same. (As disclosed in, for example, patent document 1.)
In such a pair of first and second electrical connectors to which the previously proposed measure or means is applied, as shown in the patent document 1 published previously, a first electrical connector constituting a plug type electrical connector (a plug 20) is provided with a connectively engaging protrusion which forms a plurality of protecting tongues (34) on an insulated housing (a housing 21) and on which a plurality of contacting portions (24) are arranged and a pair of engaging guide members (engaging arms 30) which faces each other with the connectively engaging protrusion between and projects to the outside of the connectively engaging protrusion and an insulated housing (a housing 71) of a second electrical connector constituting a plug type electrical connector (a receptacle 70) is provided with a connectively engaging opening (a engaging groove 80), with which the connectively engaging protrusion of the first electrical connector is engaged, and a pair of engaging receptacle openings (79) which are opposite to each other with the connectively engaging opening between and with which the engaging guide members of the first electrical connector are engaged, respectively. When the connectively engaging protrusion of the first electrical connector is put in engagement with the connectively engaging opening of the second electrical connector, first the engaging guide members of the first electrical connector are engaged respectively with the engaging receptacle openings of the second electrical connector so that the first electrical connector is guided to the second electrical connector by the engaging guide members and the engaging receptacle openings, and then the connectively engaging protrusion of the first electrical connector is engaged with the connectively engaging opening of the second electrical connector.
Further, there has been also proposed previously a pair of electrical connectors (first and second electrical connectors) wherein conductive contacts provided in the first electrical connector are put respectively in contact with conductive contacts provided in the second electrical connector. In such first and second electrical connectors, when the conductive contacts provided in the first electrical connector come respectively into contact with conductive contacts provided in the second electrical connector, a guiding projection (an engaging guide member) provided in the first electrical connector is engaged with a guiding opening (an engaging receptacle opening) provided in the second electrical connector. (As disclosed in, for example, patent document 2.)
In the first and second electrical connectors disclosed in the patent document 2 published previously, prior to the contact of the conductive contacts provided in the first electrical connector with the conductive contacts provided in the second electrical connector, the guiding projection constituting the engaging guide member of the first electrical connector is caused to engage with the guiding opening constituting the engaging receptacle opening of the second electrical connector to be received by the same so that a position at which the first electrical connector faces the second electrical connector and a direction along which the first electrical connector is moved to the second electrical connector are predetermined.    Patent document 1: Japanese Patent Publication No. 2002-93528 (Pages 3 to 5, FIG. 1)    Patent document 2: Japanese Patent Publication No. 2001-223057 (Pages 3 and 4, FIGS. 1, 2 and 4)